GardenRayne
Big ones!
It would help to know the size of the pots and how full you've filled them. Are they 5 gallon pots? Smaller? You say "I've been adding more soil to the top of the pots" which makes me wonder if they've been underfilled from the beginning. Roots at the surface? Could you show us pictures?
Without further information I agree that bigger pots sound like the logical fix. Crowding the roots will result in stunted fruit. Also, when is your first average frost date?
